Notes: Known only from fragmentary remains found only in South Africa,
Algoasaurus was probably less than half the size as Diplodocus. Discovered,
as are so many dinosaurs, in a quarry, Algoasaurus suffered the indignity
of having most of its skeleton, unrecognized by the quarrymen, pulverized
to make brick.

Notes: Alioramus had a longer head and smaller and more numerous teeth
than other tyrannosaurids. It was small and slender and it possessed six
small horns on its long snout, two side by side and four in a single row
ahead of them. Too small for defensive purposes, these horns may have been
secondary sexual characteristics, identifying males and females. Fossils
of this dinosaur were found in Mongolia.

Notes: Allosaurus is one of the best known carnosaurs. Sixty individuals,
from juveniles to adults, were found at one site in Utah. It is likely
that Allosaurus may have been the most common carnosaur of the Late Jurassic.
Despite its size, Allosaurus is thought to have been a speedy hunter, running
with a 3.7-meter-long stride at up to 20 mph. Its most distinguishing characteristic
is the presence of two short horns, above and in front of each eye.

Notes: Fragmentary remains of Altispinax have been discovered in England
and Germany. Only some worn teeth and three mid-back vertebrae are known.
On these vertebrae were long projections similar to, but shorter than,
those of Spinosaurus.

Notes: Discovered in Neuquen, Argentina, the remains of Alvarezsaurus did
not include a skull or forelimbs. A small animal, it was lightly built
with long legs, suggesting that it could run quickly. One odd characteristic
of this genus is the lack of spines on the neck vertebrae. Some scientists
believe Alvarezsaurus is related to the Mongolian Mononychus.

Notes: This unusual dinosaur is the earliest known Segnosaur. It is characterized
by its large arms and claws. It closely resembled Erlikosaurus in structure;
one of the more notable anatomical differences being a greater number of
teeth possessed by Alxasaurus vs. 31 in Erlikosaurus. While it had a toothless
beak, these tiny, leaf-shaped teeth were placed further back in the mouth
and are usually interpreted as being those of a herbivore.

Notes: Discovered in Argentina, Amargasaurus is known from fragmentary
remains. It is similar to the diplodocid family of dinosaurs. It is distinguished
from all other sauropods by the presence of elongated spines running from
its neck to its tail. The spines are paired, and it may be that they supported
not one but two sails. Amargasaurus' sail or sails would have increased
its body surface and allowed it to dissipate excess body heat.

Notes: A medium-sized member of the prosauropod family, this primitive
plant-eater was characterized by a small head, long neck and large body.
Discovered in a quarry in Connecticut in the late 1800's, only the back
half of the specimen was rescued by Othniel Charles Marsh; the front half
having already been sawed into blocks to build a bridge near South Manchester.
In 1969, more parts of the Ammosaurus were discovered when a nearby sandstone
bridge was demolished.